Commercial and residential water heaters, boilers and pool heaters typically heat water by generating tens of thousands, and even hundreds of thousands, of BTUs per hour. For many years, manufacturers of these water heaters have sought to increase the efficiency of the exchange of this heat energy from burned fuel to the water contained in the water heater. Accordingly, maximized heat exchange efficiency has long been sought by commercial and residential appliance manufacturers.
As heat exchange efficiency increases, however, such increased efficiency gives rise to the problems associated with condensation of water vapor from the products of combustion. More specifically, upon burning of a mixture of fuel and air, water is formed as a constituent of the products of combustion. It is recognized that as the temperature of the combustion gases decreases as the result of successful exchange of heat from the combustion gases to water in the appliance, the water vapor within the combustion gases tends to be condensed in greater quantities. In other words, as the temperature of the combustion gases decreases as a direct result of increasingly efficient exchange of heat energy to the water, the amount of condensate forming on the heat exchange surfaces also increases.
In application Ser. No. 12/395,894, filed Mar. 2, 2009 and incorporated herein by reference in its entirety, a system and method is described for configuring a water heater to drain condensate from combustion products. A drain port is positioned at an elevation below a portion of an exhaust passageway to drain condensate from the exhaust passageway. Application Ser. No. 61/444,341, filed Feb. 18, 2011 and also incorporated herein by reference in its entirety, describes water heaters and boilers configured to improve at least one of their performance, efficiency, cost and reliability.
Despite such developments, there continues to be a need for improvements related to the management of the condensation formed by condensing appliances such as water heaters.